RA2x Intermittent Wipers, After all the thinking...did anyone ever figure it out?

[TA-022]

i think it all started just to gain a RA40 style fixed intermitent system.

but now it seems Witzl is developing something that will be variable and hella easier that adapting RA40 gear.

[Gleno28]

Anyone tried ST141 corona stalk assembly? from memory looks like a fairly similar setup

[brett_celicacoupe]

But it's an RA40!!!?//?!!???!111

I would require only one extra do-hicky, to fill an already existing and unused hole on my dash, which you would probably need anyway to vary the intermittent speed.

hey hey hey! enuf dizrezpectin the 40'z
<-- this little RA40 will own that ill coloured baby-poo RA28 in your avatar


RA40's have a small motor in a box, running a worm-gear setup, in the driver kickpanel.

the motor spins a gear with sectioned contacts that pulses power to the wipers. the wipers only need about 0.5sec of power to do a full wipe.

once the power is recieved, the wiper gives itself power until the blades are at the off position. then, a second later, the small motor in the kickpanel gives another 0.5s of power and the wiper goes again.

itsfunny how they use a mechanical style switching system.....0.5sec ON, 2.5sec OFF, 0.5 on, 2.5 off etc

seeing as the RA23/28's have wipers that can return to rest when the switch is off, im sure it wouldnt be hard to replicate the intermittant system on the RA40's.


i believe the early model RA40's have the same stalk plug as the RA28's. later model RA40's used a different plug that wont fit

[Rcubed]

i made a variable intermittent control about 10 years ago.
i bought a stalk with an INT position and manufactured a variable timer control based on a 556 timer a couple of diodes, relays, resistors and capacitors. excepting the stalk the rest cost me around $10 [oops i forgot the failed prototypes ].

Now I made my own circuit board and drilled and soldered it all together. But it didn't just plug in either.

How did this start? Well i had a rally car [not a toyota]which didn't have int. as you can imagine, when going sideways on gravel you don't want to have to deal with the wipers not being on, nor the distraction of scraping a dry screen. So i bought a commercial control. it was supposed to be 'cut the low speed wire and insert the control'. it didn't work. the celica was pristine and had sole use of the garage and rarely got wet so it became the test bed.

the first thing you realise is that there are 4 wires controlling the 2 speed operation of the wipers. Earth, Lo, Hi, Return. return makes the wiper return to the parked position when switched off. but you can't just apply power to the lo or hi without cutting power to return else you may blow the circuit.
so to switch on int you must cut return and engage a timer cct to turn on the low.
Changing the stalk doesnt do this. rather than making yet another circuit the stalk was modified to switch a relay to allow this.

now the int cct.
a 555 timer is the simplest timing integrated cct you can get. a 556 timer is two 555s in the one IC
A 555 can operate as a voltage accumulator. the analogy is a bucket pivoting on the edge of a wall with a spring to stop it tipping over. you pour water into the bucket and when it's 2/3 full the bucket tips and lets the water out until it is 1/3 full when the bucket rights itself. if you control how fast the water goes in you can set a defined time of the cycle.
the 555 has another mode where it will fire only once and not cycle.

ok - so cut the return and then fire the low speed right? no. you have to cut the return, fire the low and then set the return again to bring the wipers back to park. You use a relay to do this.
Unfortunately, a cam in the the motor defines the park position and is an angle either side of the nominal position . So you need to have the low on for enough time to depart the park position [else they won't continue in the cycle and will stop at an annoying position in ur field of vision] and short enough so that the return can bring them back to rest. from memory i think i chose 0.6sec [not sure why now].

a 556 was used because with a 555 the bucket starts empty and so the wipers don't come on when the switch is turned on. one half of the 556 is used solely to instantly fill the other 555 'bucket' when the switch is turned on [it is in 'one shot' mode] thereby starting the wipers straight away. the second 555 is the cycling bucket with spring timer. a pot is used to control how fast the bucket fills and adjusts the length of time to wait before firing the wipers again. i made mine 4-22secs

there is only one issue. the circuit compares the 555 voltage with supply voltage. if the supply V+ drops, the 555 may appear more than 2/3 full. it will then fire the wiper at an interval less than expected. this is only apparent on longer dwell and the wiper MAY fire when you tap the brakes, turn on the headlights or heater etc. it only happens once and will then stay the original interval - no big deal. i've thought about voltage conditioning to prevent this but not worthwhile.

I'll have to digout the cct diagram and take some photos of the installation. what i have is pretty ugly as it was a work in progress and there are 2 relays outside the main box. the refinement is to include them inside so that it just becomes one unit with wires. i never bothered to complete a new version, as it works very well.

the circuit is the size of a match box and would not be much larger if all was incorporated. i thought of revising it to include a washer function [sweep while washer on + 2 more wipes] and this isn't hard to do.

if anyone is interested i'll post the circuit.

[TurboRA28]

Very good post! rep for you

[Rcubed]

here are photos of my intermittent wiper.

http://au.pg.photos.yahoo.com/ph/hot..._EdRFBQ.bFUcoL

1. shows the stalk and the pot where the choke used to be.
2. the modified stalk [either corona or RA40 don't remember]. originally the intermittent connection [green] also connected to the low speed wire [blue w/ red trace] by metal semi circle. this was cut.
3. & 4. you can see the box plus the external relay
5. the case i used was the original unit i bought
6. the rear of the case is cut to accomodate the relay i chose.
7. & 8. & 9. Copper side of board. I did this in 1993 while in Darwin
10. Component side of board. there is not really much to it.

Been sick today so i didn't get to my work where the cct diagram is. get that tomorrow.

[TurboRA28]

Bumping an old thread up.. But my ra28 stalk/switches have burned out and need replacing. While doing this I was thinking of putting a KE70 or RA40 or some newer switch stalk assembly on with intermittent wipers on it.

Anyone done this yet?

[BlueMeanie]

Seen this Joel?
http://www.toymods.net/forums/showthread.php?t=33268

I've been meaning to do this, just haven't got around to it yet.

Cheers, Jason.

[TurboRA28]

No my searching skills must suck. Thankyou i'll have a read

[Mos]

Joel, if you want you can have a variable intermittent setup from an ST205 or AE101
They may look slightly too modern tho...

[TurboRA28]

Mos, so that is using the st205 or ae101 stalk and wiring/relays etc?

[Mos]

Yep